Mystery hermit

[EugeneReef]

Bought what I thought were three red legged hermits from the LFS but once I got home I noticed one of them was a different species. Any idea what this guy is? General color is either black or dark blue banded with white or grey. I thought maybe a zebra hermit but the white bands seem too small compared to the GIS results.

 

[EugeneReef]

Here's a bigger view:

 

[Tripod1404]

Maybe Clibanarius eurysternus or another Clibanarius species. Sometimes they are simply called reef hermit crabs.

 

[EugeneReef]

Thank you! Some of the GIS results do seem pretty close. After having him for a couple of days I can report the following about his behavior: I haven't seen him eating anything since I introduced him. He likes to half bury himself in the sand for hours at a time, then takes off running for a couple of hours, then buries himself again. He is a much faster mover than my scarlet reef hermits. He's swapped shells since I added him and it looks suspiciously like a shell one of my scarlet reef hermits may have been wearing, but I don't see a dead crab anywhere and I had a few of them vanish so, I am reluctant to call him a crab killer just yet (it may have just been abandoned). Clibanarius is the same genus as blue legged hermits so, presumably his behavior might be similar? The lack of grazing concerns me though.

 

[EugeneReef]

Just FYI, this guy turned out to be no good. He started harassing one of my scarlet reef hermits relentlessly (trying to take his shell I think) and I ended up pulling him out of the tank. By harassing I mean that he would pull his own shell over the opening of the other hermits shell giving him no possibility to escape. The scarlet hermit would break free occasionally and run around the tank in a panic, only to accidentally run into this grey hermit again and the cycle would start over. I can only assume if I had let it go on indefinitely the grey hermit would have won out eventually despite being smaller than the scarlet. I am not sure if this is typical of how hermits fight but it was a disturbing to witness!

 

[Uncle99]

Good work!
Trust no crabs unless you really, really love them....
When I removed every crab, no more surprise disappearances.
Reef safe.....Not

 

[SereneAquatic]

Just FYI, this guy turned out to be no good. He started harassing one of my scarlet reef hermits relentlessly (trying to take his shell I think) and I ended up pulling him out of the tank. By harassing I mean that he would pull his own shell over the opening of the other hermits shell giving him no possibility to escape. The scarlet hermit would break free occasionally and run around the tank in a panic, only to accidentally run into this grey hermit again and the cycle would start over. I can only assume if I had let it go on indefinitely the grey hermit would have won out eventually despite being smaller than the scarlet. I am not sure if this is typical of how hermits fight but it was a disturbing to witness!

Looks exactly like my much bigger 'thin stripe' crab... he's a bastard. Has killed everything with a shell, seemingly just for fun. Even killed my much bigger hairy leg anemone crab. He's currently in an acclimation box on the side of the tank while I prep a nice, final home for him down in the sump of the display where he can't terrorize anyone.

I witnessed the same behavior you described here, except that in addition to scrounging in the sand, he was an impressive rock climber and would 'perch' at the highest point in the tank quite often.